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Interior remodel of Macgregor 22 fiberglass sailboat

Built two wooden power boats. 17 and 19 foot Spira designs. Familiar working with plywood on frames. Not familiar with 100% fiberglass sailboat structure and stability.

Enjoy sailing the boat except for all the protruding interior benches in the galley and the low sitting head room in the v-birth. I realize these components are all a part of the mold structure and stiffness of the sailboat.

My Question:
Can the benches be cut out and be replaced with fiberglass to the existing mold? Will this keep things stiff and strong if done correctly?

I would also like to lower the v-birth by a few inches and extend it out a foot as I am on the tall side. I would do this with light marine lumber wood bracing etc...

It's a daysailer with perhaps an overnight sleep. Nothing more. I don't need the benches, storage, sink and the table. Not entertaining guests. It's just me. I want to open it up and have a little lower v-birth for sitting. Very simple, not trying to add weight or a bunch of cabinets etc....It's the opposite. Just basically flatten all these protruding unneeded obstacles. I don't care about resale, the double axle trailer and motor is worth way more than the boat.

Can this be done without screwing up the trim and stability and stiffness of the boat?

The green line in the v-birth photo is the height I would like to lower the bed.
The red dotted lines in the galley photo is the area I would like to cut and flatten out for just walking space.
The center drop keel area will not be touched
The attached photos are not my boat, just pics I pulled off the web of the exact same boat.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Two schools of thought on the MacGregors, one that they were built cheap and nasty, the other that they were built light for performance and to bounce/flex away from harm like a high end whitewater kayak. In the either case, all elements in their design may be critical to strength, former thinkers would say though that beefing everything up as you replace it can only make things better, while the latter school would say it is gonna screw up the balance and impair the performance. I believe I did read that MacGregor used primitive computational finite element analysis on mini computers to design the structure, so it's going to be a matter of betting your eyeball trumps engineering.

2019: returning from being sidelined with medical probs, crossing fingers worst is over, still in "armchair enthusiast" mode for time being.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

I suspect that V-berth is quite structural. Anything put there in its place had also better be. If you have never worked inside a fiberglass sailboat, cutting grinding and sanding, you're in for a real treat! There aren't a lot of more miserable jobs in boating. I had one where somebody thought it would be a good idea to open up the berth wall and make the space under the berth a storage locker - only after cutting a hole in it, they found it full of flotation foam. A poor repair job (a hunk of plywood screwed over the hole) then allowed water in there and when I got the boat it took me two years to get the foam dried out.

I suppose you should also be aware that the changes you are thinking about will likely absolutely destroy any resale value for the boat (if that matters) unless they are masterfully done. I had a buddy who was a Macgregor dealer. They weren't bad boats for the money, but he did have to do an awful lot of touch-up and fix-up work on them before he'd send them off with their buyers.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

While you may well be correct, SeanM26, that flies in the face of every production fibreglass boat structural arrangement that I have ever seen. It is common for bulkheads, partial bulkheads, settee and bunk flats, etc., even cabinet fascias, to contribute to the overall structural integrity of the boat. Although such 'plugs' (wrong term, BTW) are inserted before the deck goes on, they are normally bonded to the hull with a high-build adhesive such as those by Plexus, and the resulting composite structure is much stronger than each of the individual parts. Right or wrong, it would be wise to know for sure before one starts cutting stuff up.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Originally Posted by mmd

While you may well be correct, SeanM26, that flies in the face of every production fibreglass boat structural arrangement that I have ever seen. It is common for bulkheads, partial bulkheads, settee and bunk flats, etc., even cabinet fascias, to contribute to the overall structural integrity of the boat. Although such 'plugs' (wrong term, BTW) are inserted before the deck goes on, they are normally bonded to the hull with a high-build adhesive such as those by Plexus, and the resulting composite structure is much stronger than each of the individual parts. Right or wrong, it would be wise to know for sure before one starts cutting stuff up.

Thank you so much for all the replies. I do have further comments on them but have to head out at the moment. Will comment this evening. Again thank you for the replies. All have been extremely helpful!!

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Originally Posted by Todd Bradshaw

I suspect that V-berth is quite structural. Anything put there in its place had also better be. If you have never worked inside a fiberglass sailboat, cutting grinding and sanding, you're in for a real treat! There aren't a lot of more miserable jobs in boating. I had one where somebody thought it would be a good idea to open up the berth wall and make the space under the berth a storage locker - only after cutting a hole in it, they found it full of flotation foam. A poor repair job (a hunk of plywood screwed over the hole) then allowed water in there and when I got the boat it took me two years to get the foam dried out.

I suppose you should also be aware that the changes you are thinking about will likely absolutely destroy any resale value for the boat (if that matters) unless they are masterfully done. I had a buddy who was a Macgregor dealer. They weren't bad boats for the money, but he did have to do an awful lot of touch-up and fix-up work on them before he'd send them off with their buyers.

I will not cut a thing until I am sure. And if I do this, I will first put pole jacks to keep the sides of the hull in it's exact shape before I cut the v-birth. I am sure it's structural and for-see the hull side walls possibly moving toward each other slightly but not visible to the naked eye. And then when I put the wood braces in and epoxy them to the side walls, I will be doing it to a deformed hull.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

I can only hope this is the case for the 22. I would be so happy! Completely gut the galley and replace with just open floor. But will not cut a thing until I have certain confirmation from a mac 22 owner who has done or a designer of the boat. Know anyone I could email?

Re: Interior remodel of Macgregor 22 fiberglass sailboat

these are my exact concerns too and why I am not cutting anything until I know for sure. It's just a bench of fiberglass that is protruding out with empty storage hole sitting right over the hull. One would think if that can be cut out and replaced with a good fiberglass patch to close it up and make it part of the floor or lower side wall, the strength is returned. If I get certain confirmation and do this job, I will put pole jacks everywhere from side wall to side wall to keep the boat in it's current shape before cutting to prevent any movement until hole is fiberglassed and hardened.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Originally Posted by mmd

While you may well be correct, SeanM26, that flies in the face of every production fibreglass boat structural arrangement that I have ever seen. It is common for bulkheads, partial bulkheads, settee and bunk flats, etc., even cabinet fascias, to contribute to the overall structural integrity of the boat. Although such 'plugs' (wrong term, BTW) are inserted before the deck goes on, they are normally bonded to the hull with a high-build adhesive such as those by Plexus, and the resulting composite structure is much stronger than each of the individual parts. Right or wrong, it would be wise to know for sure before one starts cutting stuff up.

Nothing Macgregor did was normal. It has a thick, solid fiberglass hull with a thicker, solid fiberglass keelson fore and aft of the keel trunk. The bulk heads were screwed in to place with aluminum angle brackets and .5" sheet metal screws in to the molded insert. Every single part of the interior flexed when you applied pressure to it.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Tried to think of an analogy to the molded interior vs strength of hull. The V-berth and side berths create a box structure. Think of an unopened box of Cheerios. Try to "fold" it in half and you can't do it. But if you open both ends, you can now fold it more easily. Remove the contents and it will very easily fold. Apply that same rationale to a boat. I have yet to see a fiberglass design where the molded in elements were not structural.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

I'm looking at more pictures of the 22 and it is even more Spartan than The 25.

I know everything I have said runs counter-intuitive to sailboat design. But that is how Macgregors were made. The inserts are not even glued to the hull. I managed to accidentally punch a couple holes in mine to find that it was less than 1/8 of an inch thick.

A quick internet search brings up the same question asked by the OP on several forums and you can find quite a few pictures of people who have completely changed the interiors.

Like I said, Macgregor did nothing normal. Like putting 90 horsepower outboard on a 26 foot sailboat.

Re: Interior remodel of Macgregor 22 fiberglass sailboat

Thank you Sean for taking the time to further look into this. The boat would fit my needs perfectly if I can open things up. Do you happen have any of those links I can look at. Or the proper search terms I need to be typing in. I have been searching all week but can't find any examples of extensive renovations, just the normal---add a cabinet here or there type things.